Metal treatment



Patented 25, 1938 UNITED STATES PATENT OFFICE United Engineering & Foundry Company,

Pittsburgh, Pa., a corporation of Pennsylvania No Drawing.

Application April 1, 1937,

Serial No. 134,336

10 Claim.

This invention relates to metal treatment, and more particularly to the cleaning of metal articles such as by pickling.

It is common practice to clean metal articles by pickling them in an acid solution, and then rinsing them with cold water followed by hot water. After the hot rinse the articles are dried, and if they are not to be immediately subjected to further treatment of some kind, such as rolling,

they are oiled to prevent them from rusting. The

purpose of using a hot second rinse is to hasten evaporation of the water from the metal articles so as to accelerate drying. Nevertheless, it has been found that in the short time required for the metal to dry, it often rusts, which is particularly undesirable in the case of strip steel.

It is among the objects of this invention to provide a method of treating metal articles in which rusting of pickled articles before oiling is avoided.

This invention is predicated upon my discoveries that metal articles can be prevented from misting during the time between pickling and oiling by eliminating the intervening drying step, or by eliminating any possibility of the articles drying sufllciently by natural evaporation of moisture therefrom to rust before they can be oiled, and that a protective film of oil can be applied to metal articles while they are wet. This so highly desirable result is accomplished by oiling the metal immediately after it has been rinsed in cold water and without an intervening hot rinse. Cold water of the cold rinse adhering to the metal protects it from the atmosphere, which 35 causes rust, until the metal is protected by a film of 011, because the metal can be oiled before the cold water evaporates from it sufiiciently to expose it to the air.

As indicated in the preceding paragraph, the

40 successful application of oil to the wet metal articles is also a. feature of this invention. This is made possible by the use of ordinary insoluble oil violently agitated so as to displace the water on the metal sufliciently to coat it with oil, or by the u use of oil that is water-soluble or miscible with water so that the cold water adhering to the metal will not prevent the oil from reaching the surface of the metal. While there are many insoluble and water-soluble oils which may be used in this connection, and though they are believed to be so well known in the art as to need no detailed explanation, as examples simple, nonsoluble, light mineral oils, or sulfonated oils [I mixed with alkalies such as borax and sodium carbonate, which is a common form of soluble oil, may be used.

There are several ways in which this invention may be practiced. For example, the metal may be sprayed with water-soluble oil directly after it has been rinsed in cold water, because the adhering cold water will not evaporate to a material extent between the rinsing and oiling steps. Or, instead of spraying the oil on the metal, the cold rinsed articles can be immersed in a bath of substantially pure or undiluted water-soluble oil which may be agitated to assure proper mixing with the film of cold water on the articles. On the other hand, the wet articles can be immersed in a bath of insoluble oil which is violently agitated in order to rinse or flush the water off the articles so that its place can be taken by the oil.

The preferred manner of practicing this invention is to subject a pickled metal article, directly after a rinse in cold water, to a mixture or emulsion of water and water-soluble oil, either in a spray or in a bath. By using an emulsion, only a small percentage of oil is required to adequately protect the metal, and when the emulsion becomes undesirably contaminated by pickling acid carried into it by the metal article, it is not a great loss to discard it. It is also desirable to maintain the emulsion at a relatively high temperature because the oiled metal articles will carry away less hot oil than cold oil. Furthermore, the hot water in the'watery oily film on the metal articles evaporates therefrom more quickly than cold water would. However, the temperature of the emulsion should be kept below the boiling point of water to prevent the water from boiling out of it. It has been found in practice that a temperature between 150 and 200 F., preferably in the neighborhood of 180, is satisfactory. By adding a small quantity of insoluble oil to the emulsion and vigorously agitating it, the character of the protective film is improved.

As a concrete example of the importance and great utility of this invention, a certain company installed pickling apparatus in which cofls of hot rolled strip steel were cleaned in a pickling tank, transferred to a tank containing a cold water rinse followed by a rinse tank of hot water, then dried and then oiled. During the short period of time required for drying the coils after removal from the hot rinse tank and before they could be oiled, they rusted. Based on my discoveries that the rusting was due to the drying of the coils before they could be oiled and that they could be oiled without first drying them, this highly undesirable situation was corrected in a very satisfactory manner by eliminating the drying and subsequent oiling step, and substituting for the hot rinse water an agitated bath comprising hot water, about 2 per cent oi watersoluble oil, and about 1 per cent of insoluble oil. The coils were thus protected from rust by a film of oil while still wet enough to avoid rusting before being immersed in the water-oil bath. The soluble oil and agitated insoluble oil not only mixed freely with the water carried by the coils from the cold rinse tank, and thereby reached the surface of the metal and covered it, but also made it possible to adequately protect the coils with a relatively small amount of oil.

According to the provisions of the patent statutes, I have explained the principle of my invention and have described what I now consider to be its best embodiment. However, I desire to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.

I claim:

1. A method of treating metal comprising pickling it, and oiling it while it is wet.

2. A method of treating metal comprising pickling it, rinsing it in cold water, and then oiling the metal directly after said cold rinse before the water evaporates therefrom sumciently to cause the metal to rust.

3. A method of treating metal comprising pickling it, and then while the metal is still wet oiling it with water-soluble oil.

CERTIFICATE Patent iio. 2,31 ,319.

MORRIS It is hereby certified that error 4. A method oi treating metal comprising pickling it, rinsing it in cold water, and then oiling the metal with water-soluble oil directly after said rinse while the metal is still wet.

5. A method of treating metal comprising pickling it, and then rinsing it with a mixture of water and soluble oil.

6. A method or treating metal comprising pickling it, rinsing it in cold water, and then applying to the metal a mixture of hot water and water-soluble oil directly after said cold rinse while the metal is still wet.

7. A method of treating metal comprising pickling it, immersing it in cold water, and then rinsing the metal in a bath comprising an emulsion of water and soluble oil.

8. A method of treating metal comprising pickling it, rinsing it in cold water, and then applying to the metal an emulsion of hot water and soluble oil below its boiling point but high enough to materially thin out the oil.

9. A method of treating metal comprising pickling it, rinsing it in cold water, and oiling the metal in a bath of vigorously agitated oil.

10. A method of treating metal comprising pickling it, rinsing it in cold water, and immersing it in an agitated bath comprising water and soluble oil and insoluble oil.

MORRIS D. STONE.

OF CORRECTION.

October 25, 1958. D. STONE.

appears in the printed specification of the above numbered patent requiring correction as follows: Page 2, second column, lino 1b., claim7, for the word "immersing" read rinsing; sni line 15, same claim, for "rinsing" read immersing; line 20, claimB, after "oil" insert maintained at a temperature; and that the said Letters Patent h ld be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 13th day of December, A. D. 1958.

(Seal) Henry Van Arsdal e Acting Commissioner of Patents.

very satisfactory manner by eliminating the drying and subsequent oiling step, and substituting for the hot rinse water an agitated bath comprising hot water, about 2 per cent oi watersoluble oil, and about 1 per cent of insoluble oil. The coils were thus protected from rust by a film of oil while still wet enough to avoid rusting before being immersed in the water-oil bath. The soluble oil and agitated insoluble oil not only mixed freely with the water carried by the coils from the cold rinse tank, and thereby reached the surface of the metal and covered it, but also made it possible to adequately protect the coils with a relatively small amount of oil.

According to the provisions of the patent statutes, I have explained the principle of my invention and have described what I now consider to be its best embodiment. However, I desire to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.

I claim:

1. A method of treating metal comprising pickling it, and oiling it while it is wet.

2. A method of treating metal comprising pickling it, rinsing it in cold water, and then oiling the metal directly after said cold rinse before the water evaporates therefrom sumciently to cause the metal to rust.

3. A method of treating metal comprising pickling it, and then while the metal is still wet oiling it with water-soluble oil.

CERTIFICATE Patent iio. 2,31 ,319.

MORRIS It is hereby certified that error 4. A method oi treating metal comprising pickling it, rinsing it in cold water, and then oiling the metal with water-soluble oil directly after said rinse while the metal is still wet.

5. A method of treating metal comprising pickling it, and then rinsing it with a mixture of water and soluble oil.

6. A method or treating metal comprising pickling it, rinsing it in cold water, and then applying to the metal a mixture of hot water and water-soluble oil directly after said cold rinse while the metal is still wet.

7. A method of treating metal comprising pickling it, immersing it in cold water, and then rinsing the metal in a bath comprising an emulsion of water and soluble oil.

8. A method of treating metal comprising pickling it, rinsing it in cold water, and then applying to the metal an emulsion of hot water and soluble oil below its boiling point but high enough to materially thin out the oil.

9. A method of treating metal comprising pickling it, rinsing it in cold water, and oiling the metal in a bath of vigorously agitated oil.

10. A method of treating metal comprising pickling it, rinsing it in cold water, and immersing it in an agitated bath comprising water and soluble oil and insoluble oil.

MORRIS D. STONE.

OF CORRECTION.

October 25, 1958. D. STONE.

appears in the printed specification of the above numbered patent requiring correction as follows: Page 2, second column, lino 1b., claim7, for the word "immersing" read rinsing; sni line 15, same claim, for "rinsing" read immersing; line 20, claimB, after "oil" insert maintained at a temperature; and that the said Letters Patent h ld be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 13th day of December, A. D. 1958.

(Seal) Henry Van Arsdal e Acting Commissioner of Patents. 

